AT518149A1 - Internal combustion engine - Google Patents

Abstract

Internal combustion engine (1) with a control device (2) and at least one combustion chamber (3) and an at least one combustion chamber (3) associated ignition amplifier (4), wherein the at least one combustion chamber (3) on the one hand via a feed device (5) for a fuel Air mixture can be supplied with energy and on the other hand energy can be supplied by the associated ignition amplifier (4), wherein the control device (2) is adapted, in a detection mode for the at least one combustion chamber (3), the excess air coefficient (λ) of the fuel-air - Change mixture, and at least one sensor (6) is provided, the signals of the control device (2) can be fed and whose signals are characteristic of the combustion event in at least one combustion chamber (3) and that the control device (2) is adapted to as a function of the signals supplied by the at least one sensor (6), a for a state of the at least one combustion chamber (3) associated zumi to generate a firing amplifier (4) representative detection signal.

Description

The present invention relates to an internal combustion engine having the features of claim 1 and a method for checking the condition of an at least one combustion chamber of an internal combustion engine associated with the ignition amplifier having the features of claim 15th

No. 8,290,687 B2 describes a method for determining a quantity of diesel introduced into a combustion chamber of an internal combustion engine.

The invention is used in internal combustion engines operated in lean operation. It is known that the state of a firing amplifier may gradually deteriorate (and become abnormal in this sense) over a long period of time.

The object of the invention is to be able to carry out an early detection of an impending error image of the ignition amplifier.

This object is achieved by an internal combustion engine having the features of claim 1 and a method having the features of claim 15. Advantageous embodiments of the invention are defined in the dependent claims.

By means of the invention, a state is brought about by a targeted change in the excess air coefficient of the fuel-air mixture for the at least one combustion chamber, in which case a correctly or at least acceptably functioning ignition amplifier can cause ignition of the fuel-air mixture. If the ignition amplifier no longer functions correctly or acceptably, the excess air excessively deliberately changed in an ignition-detrimental direction leads to a conspicuous combustion event or there is no combustion whatsoever. This is interpreted as a sign of an abnormal condition of the firing amplifier.

For example, the booster can be designed as a spark plug. This can be arranged in the combustion chamber itself or in an antechamber assigned to the combustion chamber. The invention makes it possible to detect a deterioration of the ignition effect (eg due to deposits, changes in the electrode geometry, changes in the geometry of a guide device connected to the spark plug or other signs of wear or aging) at an early stage.

Particularly preferably, it is provided that the ignition amplifier has an introduction device for fuel or a fuel-air mixture and is preferably designed as an antechamber or injector for a liquid fuel (eg diesel or another auto-ignitable fuel). In this case, it is possible to cause the prechamber or injector ignition to deteriorate (eg, due to deposits, changes in prechamber or injector geometry, changes in the geometry of a nozzle connected to the prechamber or injector, or other signs of wear or deterioration). detect early.

Especially with large internal combustion engines, it may be helpful for reliable ignition of the fuel-air mixture in the combustion chamber to form the booster as a pre-chamber, in which a relatively rich mixture or preferably pure fuel (which can be fed via its own feeder the antechamber - so-called rinsed Antechamber is ignited and enter from the ignition torches in the combustion chamber. In a purged pre-chamber is usually provided that about half of the energy in the pre-chamber at the time of ignition comes from the combustion chamber, the rest is supplied by the own fuel or mixture supply the prechamber. Is now z. B. provided an Abmagern the fuel-air mixture in the combustion chamber, the antechamber gets less energy and then does not ignite when z. B. too many deposits or the like. In the prechamber itself, a spark plug of the prechamber or the feeder (eg., Valve for gas or a gas-air mixture) of the prechamber are present.

It can preferably be provided that the sensor whose signals are characteristic of the combustion event in the at least one combustion chamber is designed to detect a lowering of the exhaust gas temperature of the combustion chamber or a deterioration of the smoothness.

It is preferably provided that the control device is designed to control the ignition amplifier in the detection mode for introducing an unchanged amount of energy into the at least one combustion chamber. In this case, therefore, the change in the excess air number does not take place via the booster, if this has a fuel feed device or a fuel-air mixture, but the mixture in the combustion chamber is changed. This is particularly advantageous when the supply of fuel or fuel-air mixture of the ignition amplifier is made passive, d. H. itself can not be directly influenced. Quite generally, irrespective of the exemplary embodiment discussed here, the change in the excess air coefficient of the fuel-air mixture for the at least one combustion chamber can be effected by the methods familiar to the person skilled in the art by the actuation of suitable actuators.

In order to avoid power drops of the internal combustion engine in the detection mode, it may be provided that the control device is adapted to change the boost pressure of the at least one combustion chamber via the supply fuel-air mixture such that the effect of the changed excess air ratio of the fuel-air -Memisches on the at least one combustion chamber via the supply device supplied energy can be compensated. This compensation can be done by the fuel quantity is left equal and the amount of air is increased accordingly.

The change of the excess air ratio in the detection mode can be done so that the excess air ratio is increased or decreased. An increase in the excess air pressure (leanness) causes an abnormal feeding device to specifically approach an operating point where the abnormal condition is particularly noticeable. Reducing the excess air ratio (greasing) causes an abnormal feeding device to reach an operating point at which the abnormal state (in the detection mode) is no longer effective. The combustion in the detection mode is then inconspicuous. If there is another combustion chamber with a feed device with normal properties during normal operation, combustion in the detection mode in this combustion chamber will at first cause no abnormalities. If enrichment continues, abnormalities may occur because the upper tolerance range for ignition is reached.

It can preferably be provided that the control device is designed to detect in the detection mode whether the change in the combustion event caused by the air-fuel mixture with a changed excess air quantity reaches or passes a threshold value. When this threshold is reached or passed, a detection signal is output by the controller, which indicates the state of the associated booster as abnormal. The threshold value can be a previously stored value in the control device, which originates from empirical values, measurements or physical values. It is also possible to set a tolerance band around the threshold value and to output the detection signal only when the tolerance band has been reached or passed.

It can preferably be provided that the control device is designed to detect in the detection mode whether the gradient of the change in the combustion event caused by the fuel-air mixture with a changed excess air quantity reaches or passes a threshold value. Measurements have shown that in the case of ignition amplifiers with abnormal behavior, a faster response to the change in the excess air count occurs. When this threshold is reached or passed, a detection signal is output by the controller, which indicates the state of the associated booster as abnormal. The threshold value can be a previously stored value in the control device, which originates from empirical values, measurements or physical values. It is also possible to set a tolerance band around the threshold value and to output the detection signal only when the tolerance band has been reached or passed.

It can preferably be provided that the internal combustion engine has at least two combustion chambers, each of which an ignition amplifier is assigned, each of the at least two combustion chambers is assigned a sensor whose signals are fed to the control device and whose signals are characteristic of the combustion event in the associated combustion chamber.

In such an internal combustion engine, the control device may be designed to compare the signals of the at least two combustion chambers in the detection mode and to determine in which of the at least two combustion chambers a larger change has taken place in response to the change in the excess air coefficient. For that combustion chamber in which the greater deviation has taken place, the control device can output a detection signal which identifies the state of the associated ignition amplifier as abnormal.

Such an internal combustion engine may also have at least three combustion chambers, each associated with an ignition amplifier, wherein each of the at least three combustion chambers, a sensor is assigned, the signals of the control device can be supplied and whose signals are characteristic of the combustion event in the associated combustion chamber. The control device is designed to detect in which of the at least three combustion chambers the greatest change has taken place relative to a predetermined statistical characteristic. For that combustion chamber in which the greater deviation has taken place, the control device can output a detection signal which identifies the state of the associated ignition amplifier as abnormal.

The internal combustion engine may also have a plurality of combustion chambers with associated ignition amplifiers, and the controller may be configured to selectively change the excess air ratio in the detection mode for one or more combustion chambers so as to generate a detection signal identifying the condition of the associated booster amplifier as abnormal ,

Examples of possible sensors whose signals are characteristic for the combustion event in at least one combustion chamber: • Temperature sensor for exhaust gas emitted from the combustion chamber or the combustion chamber itself • Cylinder pressure sensor • Knock sensor (structure-borne sound sensor) • Ion current sensor

The invention may be preferably used in a stationary internal combustion engine, for marine applications or mobile applications such as so-called "Non-Road Mobile Machinery" (NRMM) - preferably in each case as a reciprocating engine. The internal combustion engine can serve as a mechanical drive, z. B. to operate compressor systems or coupled to a generator to a gene sets for generating electrical energy.

As fuel for combustion in the combustion chambers is preferably gas (eg.

Natural gas) is used.

Embodiments of the invention will be discussed with reference to the figures.

1 shows schematically the construction of an internal combustion engine 1 according to the invention. The following can be seen: a control device 2 combustion chambers 3 ignition amplifiers 4 assigned to the combustion chambers 3 the supply devices 5 assigned to the combustion chambers 3 the sensors 6 assigned to the combustion chambers 3

The feed devices are supplied by means of a gas mixer 7, which mixes gas mixer 7 air L and fuel (in this case gas G) to a gas-air mixture having a certain excess air coefficient λ. The excess air coefficient λ can be influenced by means of various actuators. Examples would be in addition to the gas mixer 7, a turbo-bypass line, a wastegate or other experts known actuators. Feeders for the booster 4 (here, prechamber) are not shown because they are well known in the art (eg, pre-chamber gas valves connected to a source of gas or gas-air mixture).

The arrangement of the sensors 6 is to be understood purely schematically and depends on the choice of the type of sensors 6.

Figures 2a and 2b show schematically the signals S (solid) different combustion chambers 3 (here four different combustion chambers 3 exemplified) associated sensors 6 and the excess air coefficient λ as a function of time t. In the present case, a signal S * was chosen whose excessive or rapid decrease indicates an abnormal behavior, eg. B. a temperature signal.

At the time U up to the time t2, a first change in the excess air coefficient λ takes place for all four combustion chambers 3, in this case in the direction of leaning out. Between the times t2 and t3, the excess air ratio λ is kept constant. At time t3 to time t4, a second change in the excess air coefficient λ occurs for all four combustion chambers 3, in this case in the direction of leaning out. Between times t4 and t5, the excess air ratio λ is kept constant. At the time t5 to the time t6, a third change takes place for all four combustion chambers 3

Excess air ratio λ to a constant value. The control device 2 is located between the times ti and t6 in the detection mode.

It can be seen that in the present example the signals S except S * have a similar behavior. The signal S * has a conspicuous behavior, because this signal S * decreases faster and stronger. The control device 2 can generate such a detection signal, which states that the combustion chamber 3 associated with this booster amplifier 4 (currently only in case of load) abnormal response and therefore to check or replace.

The three unobtrusive signals S can be used to form a statistical index in the form of an expected value E or a median. Such a measure can also come from a model. By setting a maximum distance from the expected value E, a tolerance band can be defined via the expected value E. In FIG. 2a, the tolerance band is illustrated by its upper limit TO and its lower limit TU (both shown dotted). The detection signal can be generated when the indicated tolerance band is exceeded.

Alternatively, the detection signal may be generated when a gradient of a signal S * exceeds a threshold. Analogously, the limit value for the gradient can also be determined from a statistical characteristic number (for example, median or mean value), for example with an offset.

Claims (15)

claims: 1. Internal combustion engine (1) with a control device (2) and at least one combustion chamber (3) and the at least one combustion chamber (3) associated with the booster (4), wherein the at least one combustion chamber (3) on the one hand via a feed device (5) a fuel-air mixture is supplied with energy and on the other hand energy can be supplied by the associated booster (4), characterized in that the control device (2) is adapted to in a detection mode for the at least one combustion chamber (3) the excess air coefficient (λ ) of the fuel-air mixture, and at least one sensor (6) is provided, the signals of the control device (2) can be fed and whose signals are characteristic of the combustion event in at least one combustion chamber (3) and that the control device (2 ) is designed, depending on the at least one sensor (6) supplied signals for a state of the at least one Brennr (3) associated with at least one firing amplifier (4) to generate representative detection signal. 2. Internal combustion engine according to claim 1, wherein the booster (4) is designed as a spark plug. 3. Internal combustion engine according to claim 1, wherein the booster (4) has a fuel injection device or a fuel-air mixture and is preferably formed as a prechamber or injector for a liquid fuel. 4. Internal combustion engine according to claim 3, wherein the control device (2) is adapted to control in the detection mode, the ignition amplifier (4) for introducing an unchanged amount of energy in the at least one combustion chamber (3). 5. Internal combustion engine according to at least one of the preceding claims, wherein the control device (2) is adapted to change the boost pressure of the at least one combustion chamber (3) via the feed device (5) supplied fuel-air mixture such that the effect of changed excess air ratio (λ) of the fuel-air mixture to the said at least one combustion chamber (3) via the supply device (5) supplied energy can be compensated. 6. Internal combustion engine according to at least one of the preceding claims, wherein the control device (2) is adapted to increase in the detection mode, the excess air coefficient (λ). 7. Internal combustion engine according to at least one of the preceding claims, wherein the control device (2) is adapted to reduce in the detection mode, the excess air coefficient (λ). 8. Internal combustion engine according to at least one of the preceding claims, wherein the control device (2) is adapted to detect in the detection mode, whether caused by the fuel-air mixture with changed excess air ratio (λ) change in the combustion event reaches or passes a threshold. 9. Internal combustion engine according to at least one of the preceding claims, wherein the control device (2) is adapted to detect in the detection mode, whether the gradient of the fuel-air mixture with changed excess air ratio (λ) caused change in the combustion event reaches a threshold or happens. 10. Internal combustion engine according to at least one of the preceding claims, wherein at least two combustion chambers (3) are provided, each associated with an ignition amplifier (4), wherein each of the at least two combustion chambers (3) is associated with a sensor (6) whose signals the Control device (2) are supplied and whose signals are characteristic of the combustion event in the associated combustion chamber (3). 11. Internal combustion engine according to claim 10, wherein the control device (2) is adapted to compare in the detection mode, the signals of the at least two combustion chambers (3) and determine in which of the at least two combustion chambers (3) a major change in response to the change the excess air coefficient (λ) has taken place. 12. Internal combustion engine according to claim 10, wherein at least three combustion chambers (3) are provided, each associated with an ignition amplifier (4), wherein each of the at least three combustion chambers (3) is associated with a sensor (6) whose signals of the control device (2 ) are fed and whose signals are characteristic of the combustion event in the associated combustion chamber (3), wherein the control device (2) is adapted to detect in which of the at least three combustion chambers (3) the largest change relative to a predetermined statistical index took place Has. 13. Internal combustion engine according to at least one of the preceding claims, wherein the internal combustion engine (1) has a plurality of combustion chambers (3) with associated ignition amplifiers (4) and the control device (2) is designed to selectively in the detection mode for single or multiple combustion chambers (3 ) to change the excess air coefficient (λ) and generate the detection signal. 14. Internal combustion engine according to at least one of the preceding claims, wherein the sensor (6) whose signals are characteristic of the combustion event in at least one combustion chamber (3), is designed to lower the exhaust gas temperature of the at least one combustion chamber (3) or deterioration to detect the smoothness. 15. A method for checking the condition of at least one combustion chamber (3) of an internal combustion engine (1) associated with the ignition amplifier (4), wherein for the at least one combustion chamber (3) the excess air coefficient (λ) of a fuel-air mixture is changed and in dependence a signal characteristic of a combustion event in the at least one combustion chamber (3) is deduced from the state of the ignition amplifier (4) associated with the at least one combustion chamber (3).